KR101119723B1 - Microlithographic projection exposure - Google Patents

Abstract

In an exposure method for exposing a substrate which is arranged in the area of an image plane (7) of a projection objective (6), as well as in a projection exposure system for performing that method, output radiation directed at the substrate and having an output polarization state is produced. By means of a variable adjustment of the output polarization state with the aid of at least one polarization manipulation device (40, 50, 60, 70, 80) the output polarization state can be formed to approach a nominal output polarization state. The polarization manipulation can be performed in a control loop on the basis of po­larization-optical measuring data.

Description

Microlithographic projection exposure

The present invention relates to a method for illuminating a substrate disposed in an area of an image plane of a projection objective lens by at least one image of a pattern of a mask disposed in an area of an object plane of the projection objective lens, and a projection for performing such a method. Relates to a lighting system.

Microlithographic illumination methods and projection illumination systems are used in the manufacture of semiconductor components and in the manufacture of other precise structures. They are of very high resolution and low scale, such as masks or reticles on substrates coated with a photocurable resin, for example, on a semiconductor wafer with a light-sensitive layer, or photomasks referred to in the general shape according to the following: It is used to project a pattern of graduated reticles.

A projection illumination system for microlithography is provided for illumination of the mask as illumination radiation as well as the projection objective used to image the pattern of the mask along the mask and on the image plane of the projection objective. Lighting system. In this case, the light emission changed by the mask passes through the projection objective lens, which is oriented in the substrate and whose characteristics form output radiation which determines the quality of the image product. In this case, the output polarization state, that is, the polarization state of the output light emission appearing from the projection objective lens and oriented on the substrate, plays an important role in reducing the wavelength and increasing the numerical gap.

When using a conventional lithographic object having a non-high image-side numerical aperture (NA) and the object is purely refracted (diopter) in shape and operated using polarization wavelengths greater than 248 nm, the output polarization state is in most cases not critical. not. For systems that operate with polarization, such as, for example, projection objectives of polarized reflective refraction, physical beam splitters (beam splitter cubes, BSC), the output polarization state is a critical factor in contrast.

The birefringence of synthetic quartz glass is also important at an operating wavelength of about 193 nm. When using fluorinated crystalline materials such as calcium fluoride, which are used for example to correct and / or compress color errors, it should be borne in mind that these materials have a polarizing optical effect. Due to the stress induced and / or intrinsic birefringence, they can cause a polarity changing effect on the light passing through them.

At this moment, calcium fluoride is useful only in the required quality and amount for lens materials operating at wavelengths below about 157 nm. At this short operating wavelength, the effect of the intrinsic birefringence is several times stronger than at the 193 nm wavelength. Stress birefringence is often observed at disturbing levels.

Deflection mirrors can be used for the various optical systems used in the projection illumination system and are operated at an inclined angle of incidence of light, thus exhibiting polarization effects. For example, one or more deflection mirrors are provided between the illumination beam path, ie between the light source and the output of the illumination system, to reduce the physical length of the illumination unit. Due to the different reflection levels on the s-polarized and p-polarized light of the light emission from the light source, for example, partially polarized illumination light emission can be generated from the original non-polarized light emission. If linearly polarized laser light is used, the direction of the linearly polarized light can be changed or an elliptical polarization state can be generated using an appropriate phase effect. In reflective refraction systems, obliquely illuminated deflection mirrors are often provided in the area of the projection objective to have a polarization-change effect and thus affect the output polarization state.

For example, with a high numerical aperture of NA = 0.85 or more, the vector properties of the electric field forming the image will increase by itself significantly. For example, an element s oscillating perpendicular to the s-polarization element of the electric field, i. More contrast. In contrast, p-polarized light is more connected photocurable. Thus, proposals have been made to operate as specific polarized output light emission, such as normal polarization or radial polarization, for example by using a high numerical aperture. Occasionally, even circular-polarized or unpolarized light emission is desirable.

Unfavorable polarization states cause a change in the width of the structured image in that direction. Interference with the preferred direction independence of the image is often referred to as HV difference or critical dimensional change (CD variable). A change in the width of the image structure across the electric field is observed. In addition, an undesirable nonlinear relationship may occur between the size of the structure in which the image is formed and the size of the image structure. In addition, undesirable polarization states lead to telecentricity errors, resulting in undesirable deformations between different control planes. Contrast reduction is not the smallest in a system of radiation of parasitic polarization, which works with polarization and arises, for example, due to leakage conduction on the polarizing element.

European patent application EP 0 937 999 A1 describes a microlithographic projection objective having one or more optical elements which cause disturbances in the polarization distribution across the cross region of the light beam. The disturbance of the polarization distribution is at least partially compensated by a polarization compensator comprising at least one birefringent optical element having an irregularly varying thickness on its cross section. The polarization compensators have a predetermined fixed spatial variation effect function and are individually manufactured in the form of "polarization goggles" based on polarization specific data recorded on a fully assembled and controlled system, and is described by the manufacturer as It is permanently mounted to the system.

EP 964 282 A2 is induced when light passes through a reflective refraction projection system with a refraction mirror to have two or more coatings in the refraction mirror and have different levels of refraction of s-polarized and p-polarized light. The problem of the preferred polarization direction is addressed. As a result, light that is still not polarized in the reticle plane is partially polarized in the image plane, leading to direction dependence of image characteristics. This effect is correspondingly activated by generating partially polarized light in the illumination system with a predetermined residual polarization level to form polarization priority, which is compensated by the projection optics so that the polarized light is output.

EP 0 602 923 B1 (corresponding to US-A-5,715,084) is a method for converting incident linearly polarized light into circularly polarized light (equivalent to unpolarized light), in which light passes between the beam splitter cube and the image plane. An apparatus for changing the polarization state describes a reflective refractive projection objective having a polarizing beam splitter provided and operated with light of linear polarization. This is intended to ensure image contrast independent of the structural direction. Corresponding proposals are made in EP 0 608 572 (corresponding to US-A-5,537,260).

The US Pat. No. 5,673,103 patent describes a projection illumination method for a reticle structure having at least two different structural directions, which is intended to produce an image in the desired direction of light change using the flattened light. Rotatable polarization control devices are used to align optimal polarization directions of illumination light emission with respect to each structural direction by rotating optimally with respect to the structure direction.

The US Pat. No. 5,922,513 describes a projection illumination method that works with ellipsoidally flattened light. Based on theoretical considerations, these documents suggest that the degree of ellipticity and the elliptic angle are set as a function of the reticle structure to form an optimal contrast.

This invention is based on a projection illumination system that provides a microlithographic illumination method and is suitable for carrying out this method and exhibits good image performance at short operating wavelengths of about 193 nm or less. One characteristic object is to minimize polarization-dependent image error during the entire service life of the projection roughening system. An additional object is to simplify the adjustment of the projection illumination system.

In order to achieve this object, the present invention provides an illumination method having the features of claim 1 and a projection illumination system having the features of claim 17.

Desirable developments are specified in the dependent claims. The expressions in all claims are incorporated into the contents of the detailed description by reference.

In the illumination method according to the invention of the type described above, the pattern of the mask is illuminated with illumination light emission from the illumination system and thus causes light emission to be varied by the pattern. This light emission is achieved through the projection objective lens, forms an output light emission that is oriented on the substrate, and has an output polarization state. By varying the output polarization state with the help of at least one polarization manipulation device, the actual output polarization state is directed to the corresponding illumination with the faucet corresponding to the error, as specified in the illumination process for the polarization-sensitive image error. Matches the intended nominal output polarization state.

The present invention makes it possible to effectively correct polarization aberration, i.e., effects related to the vector properties of the electric field. One major advantage of the present invention is that various variable adjustments of the output polarization state can control and minimize such image errors that occur only during operation of the projection illumination system, for example in the expectation of manufacturers of semiconductor elements. Because, the residual absorption of the optical element of the lithographic object causes heating to cause mechanical stresses that alternately induce the formation or change of the birefringent effect in the correspondingly acceptable material. In this case, the spatial pattern of heating is generally device-specific and therefore not always considered by the optimized design of the projection illumination system. Further changes in the polarization effect during the duration of the projection illumination system are manifested by changing the position of the element exhibiting polarization by light-induced and contamination-induced layer degradation, stress related, or for example by dislocation or tilt. Since the output polarization state can be variably set by only proper polarization operation of the projection illumination system according to the present invention, it is possible to respond with short attention to such changes in polarization in order to maintain image performance throughout a given specification. Done.

In particular, it is possible for the illumination system and / or projection objective to have at least one optical element which disturbs the polarization distribution throughout the cross section of the beam, and the output polarization state at least partially compensates for this disturbance or interference. It can be adjusted for. Thus, at least one polarization manipulation device used for this purpose is structured and structured as a compensator for complete or partial compensation of this disturbance.

The adjustment of the output polarization state according to the invention is preferably carried out by varying during operation of the projection illumination system when used at a particular point.

The adjustment process is carried out separately from the point of use, for example, during the maintenance of the manufacturer, for example during maintenance operations or prior to initial use. Significant time and cost advantages for adjustment and maintenance are achieved by the present invention.

For the purpose of such a device, a "polarization manipulation device" has a polarization effect and can change the polarization state of incident light emission in a predetermined manner in a predetermined manner and has one or more elements which are optionally referred to as "polarization elements" in the following. Device. It is formed of two or more parts or is formed integrally. In this case, the polarization manipulator has at least two different structures called polarization manipulators or corresponding to various polarization effect functions.

Possible polarization state changes include intended position-dependent modifications of the state of polarization on the cross section of the light emitting beam. Polarizing elements having an effect that depends on the position are referred to below as "position-variable" or "space-variable". In addition, the polarization element is possible with the effect depending on the incident angle of the light emission. These are expressed below as "angle-variable". A component or polarizing element having a polarizing effect has an effect that depends on the angle of incidence and position, in which case one of its dependencies becomes the dominant factor. Angle-dependent polarization effects occur, for example, essentially by layer transfer or reflection of birefringent and isotropic layers. In the position dependent effect, elements that are configured laterally, that is, elements that are constructed on its cross section, can be used, for example, which can be for example on a diffractive or crystal optical basis. Location-dependent effects are similarly achieved by transmission or reflection on the anisotropic layer. Finally, the position-dependent effect is achieved by the positional distribution of the mechanical stresses on the material with the stress optical effect, which position can be intentionally set and variable.

The two types of polarization effects of the polarizing element depend on the installation position of each optical system. When positioned on a peripheral or pupil plane, position-variable elements operate in the pupil and angle-variable elements operate in the electric field. When located adjacent to the electric field, ie when located in or around the electric plane, this is exactly reversed. In this case, the position-variable element acts on the electric field and the angle-variable element acts on the pupil. The electric and pupil polarization states are thus influenced at least almost in isolation by the choice of installation location and possible suitable combinations.

In one embodiment, the adjustment of the output polarization state is position-variable and / or angled at a predetermined installation position of the beam path between the light source associated with the illumination system and the image plane of the projection objective, which is performed as necessary. A variable effect function, comprising the insertion of at least one component with a polarizing effect. The output polarization state can be varied by inserting a polarizing element such as a beam path or by removing it from the beam path.

Has a first effect function, which has a polarization effect and can be replaced with at least a second element, has a second effect function that is not the same as the first one, and has a polarization effect to remove the polarization element at the point of installation location It is particularly possible for the first component to be coupled together, and to select or switch among two, three or more different options for influencing the polarization state.

Alternatively, or additionally, the output polarization state can be adjusted by a stepwise method or by the continuous variability of the effect function of the at least one adjustable element with the polarization effect. This can be permanently installed in the system, but it can also be exchanged with an adjustable polarizing element.

If a polarization manipulation device is provided in the illumination system, the polarization state of the illumination light emission falling on the mask is for example to provide virtually or completely non-polarized or circularly polarized light or light that is largely linearly polarized in the mask plane. Can be adjusted carefully Arbitrary manipulation of illumination light emission affects the output polarization state and can be optimized in a corresponding manner.

This image forming method is affected by using one or more polarization manipulation devices between the object plane and the image plane of the projection objective. In this case, the polarization manipulation device may be disposed outside the projection objective, that is, between the object plane and the objective lens inlet, or between the objective lens outlet and the image plane. This is advantageous in that it makes it possible to avoid critical interference in the projection objective. In another embodiment, at least one polarization manipulation device is provided on or within the projection objective lens.

The polarization manipulation device is a replaceable device in which a suitable polarization element can be inserted into or removed from an illumination beam path or an image beam path or exchanged with polarization elements having different polarization change effects. A device is also possible for the stepwise or continuous change of the effect function of the adjustable polarizing element positioned in the beam path without exchange. For example, the position-resolving (spatial decomposition) adjustments of the different local delay effects on the retardation device may, for example, be transferred to the stress-birefringent material by an appropriate actuator based on a predetermined position distribution. It is used to change the local distribution of the polarization effect on the cross section of the polarizing element by adjusting the stress state of the constructed element. The effect function of one or more polarizing elements can be varied by changing their position, for example by rotating, dispersing, or tilting one or more birefringent elements.

In many cases, it has been found that it is particularly effective for the polarization manipulations performed on the measured polarization factors. Thus, in one embodiment, the output polarization state is measured with the aid of at least one polarization measurement device to produce at least one actual signal indicative of the current actual output polarization state. The correction required for optimization can be determined by comparing the actual output polarization state with the desired nominal output polarization state. According to the actual signal, at least one adjustment signal is generated, which is used for adjustment of the output polarization state by the at least one polarization manipulation device in order for the approach to approach the nominal output polarization state.

The actual signal is formed, for example, by angle-resolved and / or position-resolved measurements of the polarization state of the area of the field plane in the area of the image plane of the projection objective. Position-resolved measurements of polarization states in the region of the pupil plane are also possible.

This makes it possible to provide a control loop that controls the output polarization state in real time. The optical and / or electronic elements required to perform polarization control are part of a wafer stepper or wafer scanner, so that polarization control can be used in the operation of the projection illumination system. For example, measurements may be made and the projection objective and / or illumination system may be optimized by appropriate polarization manipulations while resting the manufacturing process between individual illumination steps.

In advance, it is possible to generate one or more adjustment signals for the polarization manipulation device based on a preset function provided for example in a setting table. This allows forward correction of the projection illumination system, for example, to optimize the output polarization state for certain types of illumination steps based on process-specific. The data of the preset function may theoretically be determined based on model calculations and / or experimental values.

The foregoing and further features are apparent from the drawings and the description as well as from the claims, with the individual features in each case being combined as two or more in the form of a sub-combination for embodiments of the invention or other fields. And various preferred embodiments as well as patentable embodiments in their own right.

1 is a schematic diagram of one embodiment of a projection illumination system according to the present invention.

2 is a schematic diagram of a reflective or refractive projection objective lens according to an embodiment of the present invention.

3 is a schematic diagram of one example of a polarization manipulation device having a retardation plate whose retardation effect can be variably adjusted based on position decomposition.

4 is a schematic diagram for explaining the non-uniform delay on the cross section of the delay element.

5 illustrates various embodiments of angle-variable polarization elements.

6 illustrates various embodiments of good position-variable polarization elements.

7 is a schematic diagram illustrating the formation of structure-induced birefringence in a sub-wavelength grating.

8 shows an embodiment of a polarizing element with sub-wavelength gratings structured differently.

FIG. 9 shows a variant of the polarization element for position-decomposing the desired polarization state to any desired polarization state with the λ / 4 and λ / 2 delay devices connected in series.

10 illustrates various embodiments of polarization elements of the type shown in FIG. 9.

FIG. 11 shows an embodiment of a polarizing element (λ / x retarder) that changes from linearly polarized light to any desired elliptical polarized light or vice versa.

FIG. 1 shows an embodiment of a projection illumination system 1 for microlithography fabrication of integrated circuits and other finely structured elements with reduced resolution to the level of 1 micron. The installation part 1 is the exit of the illumination system as well as the projection objective 6 for imaging a pattern of photomasks arranged in the object plane 4 on the image plane 7 of the projection objective lens at a smaller scale. Or an illumination system 2 for illumination of the photomask 5 arranged in the image plane 4. A semiconductor wafer coated with a photosensitive layer is for example disposed on the image plane 7.

The laser 8 is a light source for the illumination system 2, for example an excimer laser used for deep ultraviolet bands (DUV), the operating wavelength of which is 248 nm, 193 nm or 157 nm. The light of the light beam that is emitted is largely linearly polarized. The downstream optical device 9 forms the light of the light source and delivers it to the downstream light mixing device 10. In the embodiment shown, the optical device 9 is arranged downstream of the laser 8 and is used for reducing the consistency and forms a beam beam cross section of a square with an aspect ratio (x / y) of one or more side lengths. And a beam expander used for the purpose. A first diffractive optical raster element directed downstream from the beam stretcher is disposed on the object plane of the downstream zoom axicon objective lens provided with a second optical raster element in its pupil plane. Such devices allow lighting systems to switch between, for example, general lighting with variable coherence and bipolar or quadrupole lighting between different lighting modes. The light enters an input optic which transmits light to the inlet surface 11 of the light mixing device. The light is mixed and homogenized by multiple internal reflections within the light mixing device 10 and exits the outlet 12 of the highly homogenized light mixing device. The light mixing device is immediately adjacent to the outlet so that there is an intermediate field plane so that the adjustable field holes in the reticle mask system (REMA) 13 are arranged. The downstream objective 14, referred to as the REMA objective, comprises two or more groups of lenses, a pupil plane 15 and a refractive mirror 16, the intermediate field plane of the reticle mask system on the reticle or photomask 5 Image it.

Further details on the structure and method of operating the lighting system for such are described for example in EP 0 747 772 A1, the content of which is incorporated herein. Embodiments without a light mixing device are also possible.

In the case of a wafer stepper, the entire structural surface corresponding to a rectangular chip, typically having a desired aspect ratio of height and width of 1: 1 to 1: 2, is irradiated as uniformly as possible, with the edges as sharp as possible on the reticle 5. Is formed. In the case of the above-described type of wafer scanner, narrow strips, for example aspect ratio rectangles of 1: 2 to 1: 8, are irradiated on the reticle 5, and the entire structured field of the chip is in the y direction of the illumination system. It is irradiated in a continuous shape by scanning in the direction corresponding to. In this case, the illumination is very uniform and is designed to provide sharp edges at least perpendicular to the scanning direction, ie the x direction.

As an exception, other shapes of the illumination surface on the photomask 5 are also possible. The opening of the reticle mask system 13 and the cross-sectional shape of the light outlet 12 of the light mixing device 10 exactly match the required field shape. For example, the width in the x direction is at least twice the total height in the y direction (scan direction).

An apparatus 20 for supporting and manipulating the mask 5 is arranged behind the illumination system so that the mask is arranged in the object plane 4 of the projection objective lens and is intended for scanning in the starting direction (y direction). It can be moved by the scan drive in the plane.

The projection objective 6 follows the mask plane 4 and acts as a reduction objective, for example by expressing an image of the pattern as an image in a reduced ratio of 1: 4 or 1: 5, thereby providing a photosensitive layer. An image of the pattern disposed in the mask is embodied on a wafer which is covered with and arranged on the image plane 7 of the reduced objective lens. As another scaled down scale, it is also possible to scale down to 1:20 or 1: 200, for example. The wafer 21 is supported by an apparatus 22 comprising a scanner drive to move the wafer parallel to the reticle 5.

The polarization measuring device 30 is arranged in the beam direction behind the wafer plane 7 and allows the output polarization state of the projection illumination system, ie the polarization state of the output light emission oriented in the wafer to be measured. In an exemplary system, position-decomposition and angle-decomposition measurements of the field of the wafer plane 7 are also possible, another embodiment of the projection objective 6 corresponding to the resolution angled at the exit of the projection objective. It is designed for position-decomposition measurement of the exit pupil 16. The measurement signal from the polarization measuring device is processed by a control device 31 connected thereto and arranged in one or more polarization manipulation devices 40, 50, 60, 70, 80 arranged at selected installation positions of the beam path of the projection illumination system. Polarization measurements to form a control signal for

In the illustrated embodiment, the polarization manipulation device 40 is provided at an installation position adjacent to a field around the middle field plane of the exit of the rod integrator at the entrance of the objective lens 14, and the polarization manipulation device 50 is provided in the area of the pupil plane 15 of the objective lens 14 to allow adjustment of the polarization state of the illumination light incident on the reticle plane 4. A polarization manipulation device 60 adjacent to the field and at the entrance of the objective lens, a polarization manipulation device 70 in the pupil 16 of the projection objective lens adjacent to the image field and adjacent to the pupil, and directly to the image plane An additional polarization manipulation device 80 adjacent to, i.e., adjacent to, the field is provided to the projection objective 6. In most embodiments, only a portion of this polarization manipulation device is provided, for example in the periphery of the field plane located outside the optical system, before or after the reticle plane 4 or just above the wafer plane 7, or the projection objective. It can be placed in a lens or other mounting position of the lighting system.

2 shows one embodiment of a projection objective 106 in the form of a reflective or refractive projection objective with polarization selection, physical beam splitting. It has an objective lens portion 125 between its object plane (mask plane 104) and its image plane (wafer plane 107) and a pure photorefractive object portion 126 behind it. The reflective refractive objective portion includes a concave mirror 127 and a beam refracting device 128, forming an actual intermediate image disposed in or spaced apart from the area of the beam splitter 129. The beam refracting apparatus includes a physical beam splitter 129 having a polarization-selective beam splitter layer 130 that is inclined with respect to a portion of the optical axis 131 perpendicular to the object plane. The beam refracting apparatus includes a refracting mirror 132 disposed in the light path directly behind the beam splitter, and with respect to the reflection on the beam splitter layer, allowing the object plane and image plane to be placed side by side to allow scanner operation. Simplify Since one and only one actual intermediate image is formed, two interrelated optical pupil planes are defined between the object plane and the image plane, ie the cavity plane 136 adjacent to the image and the adjacent pupil plane 135 of the concave mirror and It is located in the pupil plane of the beam refracting objective portion. The pupil plane is generally not exactly flat and may be referred to as the pupil surface.

For example, the illumination system is designed to emit linearly polarized illumination light. In order to simplify the structure-direction independent image, the reticle is illuminated with circularly polarized light. To achieve this, a device, for example in the form of λ / 4 plate 140, is arranged between the outlet of the illumination system and the reticle plane in order to convert linearly polarized light into circularly polarized light. The projection objective itself is designed to work with circularly polarized light, for example to convert the circularly polarized light into light that is s-polarized and thus highly reflective to the beam splitter layer 130. And a device in the form of λ / 4 plate 141 between the beam splitter and the beam splitter. A polarization rotating device 142 is disposed between the beam splitter layer 130 and the concave mirror 127 and acts as a λ / 4 plate, so that the preferred direction of deflection is 90 degrees when light passes through it twice. In turn, the light reaching the beam splitter layer on the return path from the concave mirror is p-polarized against it and, thus, is transmitted. In the diffractive objective portion, an additional retardation device 143 which acts as a λ / 4 plate is provided around the pupil plane 136 between the refractive mirror 132 and the image plane, and the incident linearly polarized light is not polarized. It is converted into circularly polarized light equivalent to light.

If leakage transfer of residual elements of p-polarized light occurs in the beam splitter layer, this light is trapped in the light trap 145.

The intensity inhomogeneities of the field are modified in this embodiment by the delay effect of the delay devices 140, 141 disposed adjacent to the field set on the location-decomposition mechanism, so that the delay effect is nominal. It is locally different from the value λ / 4. The light on the retardation device 141 is polarized in an ellipse at this spatially defined location so that the light is not all reflected on the beam splitter layer 130, but part of it passes through the light trap 145. . The nominal λ / 4 value should be chosen so that the interference to be corrected is greatly compensated.

The intensity heterogeneity in the pupil is similarly corrected by the delay effect of the delay device 142 which is locally different from the nominal λ / 4 value. At this point, light in the optical path behind the retardation device 142 is not purely p-polarized but is ellipsoidally polarized so that the light is not entirely transmitted to the beam splitter layer, and part of it is reflected. . The discrepancy from the nominal lambda / 4 value must be selected again so that the interference to be corrected is greatly compensated.

Each of the delay devices 140, 141, 142, 143 can be used as an adjustable polarization manipulator by varying the wafer side output polarization state. Possible design structures will be described with reference to FIG. 3.

FIG. 3 allows position-decomposition control of locally different retardation effects on the retardation device, wherein the position-resolved parameter of the effect function of the polarizing element is changed by the spatial or local distribution of the polarizing optical retardation effect on the cross-section of the polarizing element. It is used as a reference to describe an embodiment of the polarization operation device 150 that can be variably adjusted to be possible. The polarization manipulator 150 is a plane-parallel plate composed of calcium fluoride whose crystallographic <100> axis is aligned perpendicular to the plane of the plate and which is intended to be arranged essentially parallel to the optical axis in its installed state. 151. The rows of actuators 152 which can be individually electrically actuated are in each case coupled on the circumferentially opposite longitudinal sides of the saga-shaped plate, for example measured piezoelectric elements, motor driven micrometer screws or step downs. It may be in the form of a stepper motor. Due to the stress-birefringent feature of the fluorinated crystal material, a mechanical preload is formed on the plate 151 so that a calcium fluoride plate of appropriate thickness has the effect of λ / 4 plate uniformly over its entire cross section. Regarding the design of a delay element with a predetermined uniform delay effect of stressed calcium fluoride is described in US Pat. No. 6,324,003 B1. Examples for stress-birefringent flat plates composed of quartz glass are described, for example, in Applicant's US Pat. No. 6,141,148 (corresponding to EP 0 942 300). The description of this embodiment is incorporated herein by reference.

In contrast to the conventional device, the polarization manipulation device of the present invention is operated by careful operation of the pressure-forming actuator 152 on the retardation plate 151 in order to allow position-dissolved calibration, which can each be adapted to an instant system state. It is possible to form different delay effects locally depending on the delay shape which can be predetermined. The time-varying correction function can be set via a driven actuator in order to perform a continuous variable between different spatial distributions of the delay effect. In this case, the position resolution can be adjusted by the number of actuators 152, the shape of the field 153, the distance between the corresponding polarization manipulation device and the adjacent field plane and is dependent on the material properties of the plate material.

When using a wafer scanner of the type described above, the main factor is the averaged delay on the scanner slit. This is illustrated schematically in FIG. 4. In this case, the solid line represents the field shape of the average delay Vm in the scanning direction (y direction) as a function of the x position. This is set on the position-decomposition basis by adjusting the stress force on the plate formed by the actuator 152 so that the average intensity shape Im is simulated on the field (indicated by the broken line) and corrected in the corresponding manner. do. This makes it possible to partially or virtually fully compensate for the intensity foreign objects on the field. Corresponding position-decomposition correction in the pupil area is made possible by proper placement of such polarization manipulation devices around the pupil.

In the case of a projection objective of the type described above provided with a λ / 4 plate or a comparable retarder, this change in polarization manipulation is achieved without additional optical components, since the existing retardation element can be replaced with the polarization manipulation device according to the invention. Can be performed. The extreme calibration range is possible because it depends on the delay, the calibration assumes an arbitrary value of 0-100%, and the position function has the desired generally symmetrical shape.

Each delay device 140, 141, 142, 143 is designed in a manner similar to a polarizing manipulator with one or two suitably positioned manipulators. A polarization manipulator of the type shown is mounted in a reflective concave projection objective with geometric beam splitting, in a pure diffraction projection objective, or in an illumination system. Different delay effects, for example λ / 2 plates, are used in a similar manner for position-decomposition, variable settings of specific delay effects.

In order to control the polarization state to a reliable level, several embodiments are prepared for the factors inducing the converted pressure and / or the pressure they induce and / or their location being monitored. Alternatively or additionally, a measuring step for the selected polarization state is provided for this purpose to allow careful trimming of the delay element. In particular, for stressed rectangular plates, it is worth designing these to be rotated in order to provide variable birefringent axis positions for different devices.

As an option for the rectangular plate, it is also possible to provide a rounded stress-birefringent disc with two or more radially actuating actuators arranged on its circumferential surface in order to carefully manufacture a particular radial or tangential birefringent shape.

There are a variety of additional possible ways of providing a polarization manipulator with a polarization effect that can be carefully adjusted and, if necessary, varied in the state of funeral. For example, the delay device (delay) is rotatably mounted, in particular to allow rotation about the optical axis. The rotation of the plane-parallel plates in this case does not cause any change in the scalar optical effect. However, even if the stress induces a deformation of the wave front, it can be provided that the plate thickness is sufficiently small or the effect can be corrected by the scalar means. In addition, the axial potential of the plane-parallel plate stressed not to be homogeneous is significant only in the polarization state, but not in the scalar equiphase plane. In principle a polarizing layer is possible which can be induced by a stressed or stressed lens which can be rotated without any scalar optical effect. It is also possible for the axial dislocation of the wedge to rotate and / or consist of at least one birefringent material. For example, stressed calcium fluoride or for example magnesium fluoride may be used for this purpose, if desired, they may be wrung or otherwise fixed on the calcium fluoride substrate. . Rotary diffraction sub-wavelength gratings are also possible. The principle of operation of these elements is described in more detail below. It is also possible, optionally or additionally, to slant the appropriate polarization element for polarization manipulation with respect to the rotation about the optical axis and the dispersion in the transverse direction thereto.

The adjustment of the output polarization state by changing the polarization characteristics of the projection illumination system is such that a fixed, predetermined polarization optical effect is inserted as required, removed from the beam path, or replaced with a polarizing element with other effect functions with the aid of a suitable exchange device. By means of a polarizing element. This is preferably done as a function of the polarization measurement data for an output polarization state close to the desired level of requirement.

An example of the angle-variable polarization element will be described with reference to FIG. 5, but FIG. 6 shows an example of a (leading) position-variable (spatial-variable) polarization element. The flat plate 201, which is shown in FIG. 5 (a) and composed of stressed calcium fluoride, forms an angle-variable polarization element 200 and has a delay effect depending on the angle of incidence. In this case, if the incident beam 202 is parallel to the optical axis, then the optical path length difference OPD1 will vary between the mutually perpendicular elements of the electric field vector depending on the degree of ball refraction and the thickness of the material through which the beam passes in the proper direction. Will occur. In the case of the beam 203 angled to the optical axis, the length of the optical material through which the beam passes becomes larger, and the degree of birefringence is different from when the beam passes in the axial direction. In total, the optical path OPD2 for the field element is thus not equal to OPD1. As a result, the delay effect depends on the angle of incidence. The angle-variable polarization element 210 of FIG. 5 (b) comprises a clear substrate 211 to which a dielectric multi-layer system 212 with an isotropic birefringence effect is applied at its entrance. Similar to the birefringent plate, the delay effect depends on the angle of incidence and different optical path length differences OPD1, OPD2 will appear within the layer system.

In particular, such a layer system is a multi-layer system with such a plurality of individual layers in which two or more individual layers have a smaller optical layer thickness compared to the operating wavelength of the illumination light. As a result, so-called form birefringence appears.

6A-6C illustrate an example of a dominant position-variable polarizing element that is symmetrical, for example having a radially symmetrical or rotationally symmetrical spatial effect function or having an asymmetrical spatial effect function. The polarizing element 220 has a planar-parallel plate 221, on which the diffractive structure 222 is applied, in order to carefully form a position-dependent birefringence distribution at its inlet side. Such structures form structure-derived birefringence (structural birefringence), which is determined when the periodic length of the structure is small compared to the operating wavelength used (sub-wavelength or sub-λ structure). In the case of sub lambda structures, no coherent high diffraction order occurs. In some cases, these layers have anti-reflective effects at the same time. In an exemplary system, gratings with different grating constants g1 and g2 and structure widths b1 and b2 are disposed along each other to produce optical path length differences OPD1 and OPD2 depending on the position of incidence.

및

)들은 아래의 유효 매체 모델에 따라 계산된다.The method of operation of the sub-λ grating will be described in more detail in connection with FIG. 7 which schematically illustrates the inherent polarization of the linear sub-λ grating. For a small grating top, the intrinsic polarizations, each perpendicular to the grating groove,

And

) Are calculated according to the effective media model below.

In this case, F is the following equation from the lattice constant (g) and the structure width (b)

The filling factor obtained from.

n is the refractive index of the medium and n ₀ is the refractive index of the surrounding environment. For example, when n = 1.58 and n ₀ = 1, the optical path length difference and birefringence (OPD = n _TM -n _TE ) of size between 0 and 0.13 are made according to the filling factor, for example, 10 nm A lattice depth of /0.1272 = 78.6 nm is needed for F = 0.5 to obtain a birefringence of 10 nm. In addition to the linear birefringence distribution described by way of example, radial or tangential birefringence distributions are possible by means of suitable circular sub-λ gratings, and more general birefringence distributions, possibly asymmetric birefringence distributions, are possible by more general gratings. .

Since the optical path length difference that can be achieved is generally in the order of several nm, the sub-λ structure is preferentially preferred for compensation for small optical path length differences on the cross section of the beam of light. Otherwise, the required aspect ratio for a given sub-grid will be rather large. This can be overcome, for example, by using a complex of two or more elements disposed behind one another. Composites of volume birefringence (stress birefringence and intrinsic birefringence) are also possible, for example, it is also possible to use diffractive structures to compensate for residual polarization errors of birefringent crystals. Large lattice periods have already been mentioned, but the effects are no longer calculated based on effective media theory. Finally, the diffractive structure can be incorporated into a high refractive index substrate or a high refractive index coating. This enables high birefringence (optical path length difference) at low aspect ratios. Polarizing elements having two or more sub-wavelength structures of the type disposed behind one another are described in more detail with respect to FIG. 8.

6a and c show different possibilities for dominant position-variable polarization elements. In this case, the polarization element 320 of FIG. 6B has a plane-parallel transparent substrate 321 on its inlet retardation plates 322, 323 of different thickness, with different birefringences OPD ₁ , OPD ₂ . Each is applied along each other. This results in the desired positional distribution of the abdominal fracture effect on the cross section of the polarizing element (see FIG. 11). The corresponding effect is also exhibited by the anisotropic coating of the type shown in FIG. 6C. For this purpose, anisotropic coating 342 is applied to the transparent substrate 341 (wedge or lenticular or flat-parallel flat), and in order to obtain the desired positional distribution of the birefringence effect, each with different birefringence ( OPD ₁ , OPD ₂ ) have areas 343 and 344.

The polarization element described last has a certain angle-variable and / or position-variable effect fixed on its cross section. This is used to set the desired polarization state by inserting one or more such elements as needed for the beam path of the optical system or by removing them from the beam path. For this purpose, the polarization manipulator can be designed as an exchange device in the same manner as the manipulators 40, 50, 60, 70, 80 shown in FIG. In general, such exchangeable polarizing elements can be mounted at any point in the optical system. In particular, in this case, the periphery of the pupil or the periphery of the field can be freely selected for design purposes. In this case, the position of the periphery of the hole (eg the area of the pupil 16 in FIG. 1) is particularly useful. On the other hand, freely accessible locations from the outside are also of interest. As a result, exchangeable hardware complexity is minimized. In the case of purely refractive projection objectives, for example, there may be elements positioned close to the ends of the objective lens, ie the reticle or wafer (see elements 60 and 80 in FIG. 1). The polarizing element 80 of FIG. 1 may be an interchangeable closure plate, for example in the form of the polarizing elements shown in FIGS. 5 and 6. The area of the concave mirror is added to this of the reflective refraction system (see polarization element 142 of FIG. 2). Adjacent to the periphery, the final boundary surface of the mining system can be provided and / or coated on the sub-λ structure, for example.

In terms of exchangeability, the mask and wafer can themselves be used as a location for the polarizing element. For example, a polarizing filter is coupled onto a so-called "hard pellicle" adjacent to the reticle. It is possible to coat the mask (reticle) or to cover it with a raster having an oriented and microscale structured face, so that the desired polarization is achieved in accordance with each reticle structure. For example, a polarizing filter of the type shown in FIG. 5A or 6C may be provided on a wafer by a suitable coating on a photosensitive layer (top-anti-reflective coating). In general, the polarizing element on the reticle or wafer has the advantage of meeting the requirement for a shorter stringency life than the element in the optical system.

In addition, the polarization effect in the illumination system depends on the position of the polarization element. On the other hand, in principle, all positions in the illumination optics are available with respect to the interchangeable polarization elements, and at the end or input group 9 of the projection objective (eg polarization manipulator 40 of FIG. 1). The end is suitable for this element in addition to the area of the pupil 15 of the objective lens 14 (polarization manipulator 50 of FIG. 1) forming the image. Also useful is the reticle rear face.

Structure-derived birefringent diffractive elements are used to generate multiple polarization transformations. The conversion of input luminescence with any desired ellipticity into circular polarized light is of particular importance in the art of lithographic optics. This can be achieved by a "diffractive pseudo-depolarizer." In this case, this is

)을 구비한 회절 요소를 의미한다.Jones matrix, which can convert polarized light emission with an ellipticity greater than zero to circular-polarized light emission

Means a diffraction element with

)에서의 선형 복굴절 구조체에 대하여, 상기 존스 매트릭스는 아래 와 같이 된다.Angle(

For a linear birefringent structure at), the Jones matrix is

또는

)에 대한 해결안이 구해진다.In order to find an appropriate polarization element for a given input polarization state, the Jones matrix described above may be substituted with the equation described above, and the angle (

or

Solution is obtained.

(각도 배향) 및

(지연)에 반대가 된다.For linear-polarized input light emission, the solution is a properly rotated [lambda] / 4 retardant. As the input light becomes more ellipsoidal, the required delay is shorter and the minimum along the orientation of the angle becomes wider. In this case, the two variable parameters a and α describing the input polarization are two unknowns of the birefringent element.

(Angle orientation) and

The opposite is true.

More general polarization transformations include at least a delay group having a first delay device having a first delay effect and at least one second delay device having a second delay effect that is not the same as the first case. For example, FIG. 8A shows two sub-wavelength structures 403, 404 of different dimensions in different directions and / or structural parameters (lattice top, structure width) placed behind each other in the direction of light transmission. A polarization manipulator 400 is shown that includes retardation plates 401, 402. When using a diffractive structure to retard, as shown in FIG. 9B, two or more differently oriented and / or dimensioned diffractive structures 452 and 453 are received on a common substrate 451. It is possible to provide

For delay groups having at least two delay devices (delays) with different effects, the known break down of the Jones matrix is used as the product of the "base matrix". Thus, the two products that rotate with each other are lambda / 4 delay and lambda / 2 delay (V. Bagini R. Borghi, F. Gori, F. Frezza, G. Schettini, GS: Spagnolo, "The Simon Mukunda Polarization gadget" , Eur J. Phys. 17 (1996) pages 279-284). Also within the scope of the present invention, a first delay device having a λ / 4 delay effect, a second delay device having a λ / 2 delay effect and a third delay device having a λ / 4 delay effect are provided in this order. It is also possible to use a delay group as a polarization operation device. In this case, the individual retarders are provided as described above by means of a sub-wavelength structure, a coated substrate or other suitable retarder, for example a plate of birefringent material of appropriate thickness.

The delay apparatus in this case has the same delay effect on the whole available cross section. It is also possible to use a delay device which comprises a number of individual delay elements on its cross section and which is arranged in a raster arrangement, in particular for advancing the region longitudinally. The individual retardation elements are in this case different with respect to the absolute value of the retardation effect (λ / x) and / or with respect to their axial bang orientation (the orientation of the crystallographic major axis of the birefringent material). Various embodiments of the polarization manipulation device having this type of delay group are described with reference to FIGS. 9 to 11.

9 schematically illustrates polarization element 500 by which the desired polarization state of incident light emission can be converted to the desired polarization state of output light emission on a location-decomposition basis. The polarizing elements are arranged laterally next to each other in the direction of light propagation and in the shape of a plate and comprise three individual hexagonal retardation elements 510, 511, 520, 521, 530, 531 on their illuminated cross section 501. , 502, 503, each delay device being disposed immediately adjacent to each other, inevitably advancing the surface longitudinally. Each of the retardation elements 511, 521, 531, or 510, 520, 530 disposed behind each other in the direction of light propagation has a different orientation of the optical axis (indicated by the double arrows) of the birefringent material and is defined as a whole. It forms a plurality of optical channels each having a change effect. The first delay elements 510 and 511 with the λ / 4 delay effect, the second delay element with the λ / 2 delay effect, and the third delay elements 530 and 531 with the λ / 4 delay effect are each Arranged in order in the optical channel. As already described with respect to FIG. 8, the combination of these two lambda / 4 delays and one lambda / 2 delays in the order lambda / 4-lambda / 2-lambda / 4 is achieved with any desired output polarization state, even. The desired polarization state of the fully polarized output polarization state is achieved from the input light emission. In order to achieve sufficiently precise position resolution, raster arrays and / or segments or face arrays having at least 4, 10 or 50 individual delay elements can in each case be provided in the preferred embodiment, the crystallographic The axes can be rotated as desired relative to each other. Possible methods of the structural shape of the individual retardation devices, which are in the form of plates, are known, for example, from EP 0 764 858, which is incorporated herein and described. The individual retardation elements are formed by substrates with sub-wavelength structures and / or coated substrates.

Two preferred possible ways of implementing this delay group will be described with reference to FIG. One possibility (FIG. 10A) is to press each of the individual retardation elements 610, 611, 612 on one side of the substrate to fill the surface and in other ways to fix them in an optically neutral manner. For the raster retarder device, for example, use transparent substrates 601, 602, 603 separated in the form of plane-sided plates. The polarization element 650 shown in FIG. 10B is of the same shape but it is possible for three retardation elements 651, 652, 653 with different orientations of their crystallographic axes to press directly on each other for each optical channel, such a sandwich. The structure is pressed onto the transparent substrate 660.

One embodiment of polarizing element 700 is described with reference to FIG. 11, among others, allowing the linear polarization state of light incident to the desired elliptical polarization state of the output light to be converted or vice versa. In this rasterized polarizing element, a number of individual birefringent retardation elements 702, for example with hexagonal shapes, are arranged on a plane-parallel transparent substrate 701 to advance the surface longitudinally. Adjacent retardation elements 702 and 703, which each form separate optical channels, differ in this case with respect to the orientation of the crystallographic axis and with respect to the absolute value of the delay achieved. With respect to incidence, the elliptical orientation of linearly polarized light, elliptical polarized output in each channel is in this case determined by the orientation of the retarder axis, and the degree of ellipticity is determined by the degree of delay or its absolute value. The degree of delay, i.e., the formed optical path length difference, is in this case explained by a parameter of lambda / x, where x is preferably greater than 1, in particular more than two.

FIG. 11 shows a λ / x delay with different thicknesses and separately fabricated delay elements 702 and 703 pressed onto the substrate. Optionally, by removing the material it is possible to form "cells" having different strength delays from the integral initial material, for example by etching. It is also possible to use diffractive structures similar to FIG. 6A.

The shaped polarization-changing optical element shown in Figs. 9-11 is for example illumination of the projection illumination system to retroactively compensate or precede undesirable changes in the polarization state of light from the light source caused by the system element. Used for system In particular, it is possible to correct the polarization effect of the light mixing rod 10 of a system with a linearly polarized light source. For example, the location-resolution delay of the type shown in FIG. 9 or FIG. 10 converts the linear input polarization into an elliptic output polarization such that the linear polarization state is again shown on the pupil plane 15 of the illumination system. ) And the area of the pupil plane between the rod inlet 11. When retrospectively correcting the polarization effect of the elements of the illumination system, such a position-resolved polarization element is used to convert the elliptical polarization state of the area of the pupil plane back to a linear polarization state at the output of the illumination system. Can be used in 15).

All polarization elements described herein with a fixed, predetermined position-resolving and / or angular-resolving, polarization-changing effect are used as interchangeable polarizing elements such that these elements are inserted into the beam path or projected in a defined manner. It can optionally be removed therefrom with the aid of a suitable exchange device to set the output polarization state of the illumination system.

The aforementioned polarizing elements are used in the context of the polarization manipulation device according to the invention. All polarization elements and polarization varying optical elements described herein with angle-variable and / or position-variable effects can be applied to projection optics or illumination systems or other fields, such as microscopy for microlithographic projection illumination systems. It can be used independently to exchange it in the field or in the field of other projection systems. This applies for example to the described polarizing elements with the variable adjustable polarization change effect on the adjustable delay system described in connection with FIGS. 2 to 4.

Claims (42)

An exposure method for exposing a substrate disposed in an area of an image plane of a projection objective lens of a projection exposure system by at least one image of a pattern of a mask disposed in an area of an object plane of a projection objective lens. Illuminating the pattern with illumination radiation from an illumination system to form radiation that is varied by the pattern; Passing light emission changed by a pattern through the projection objective to form output radiation oriented in the substrate and having an output polarization state; Measuring the output polarization state using at least one polarization measuring device for generating an actual signal indicative of a current actual output polarization state; Variably adjusting the output polarization state as a function of a control signal derived from the actual signal using at least one polarization manipulation device to ensure that the output polarization state approaches a nominal output polarization state intended for exposure. Include, The measurement of the output polarization state is carried out during the position-decomposition measurement of the polarization state of the area of the pupil plane of the projection objective lens or the angle-decomposition and position-decomposition measurement of the area of the field plane of the projection objective lens. At least one exposure method. delete The method of claim 1, And said output polarization state is adjusted during operation of the projection exposure system at the site of use of said projection exposure system. The method of claim 1, And said polarization manipulation device comprises at least one polarization element arranged at an installation position arranged at or around the pupil plane of the optical system. The method of claim 1, And said polarization manipulation device comprises at least one polarization element arranged at an installation position in or near the field plane of the optical system. The method of claim 1, At least one of the illumination system and the projection objective has at least one optical element which disturbs the polarization distribution on the cross section of the light emission beam, wherein the output polarization state is adjusted such that the disturbance is at least partially compensated for Way. The method according to claim 1, Adjusting the output polarization state may include selectively inserting at least one polarization element having a predetermined effect function at a predetermined installation location in a beam path between a light source associated with the illumination system and an image plane of a projection objective. Exposure method comprising the. The method of claim 1, Adjusting the output polarization state includes exchanging a first polarization element with a first effect function and at least one second polarization element with a second effect function different from this first effect function. Exposure method. The method of claim 7, wherein Adjusting the output polarization state comprises stepwise or continuously changing the effect function of at least one adjustable polarization element disposed in the beam path. The method of claim 9, Changing the effect function comprises position-decomposing and adjusting locally different retardation effects on a retardation device.  The method of claim 1, Generating at least one adjustment signal for at least one polarization manipulation device based on a preset function; And adjusting the output polarization state as a function of the adjustment signal.  The method of claim 1, And the polarization states of the projection exposure system are essentially independent of each other on the field and on the pupil.  The method of claim 1, And the polarization state of the output of the illumination system is optimized to minimize the change in the polarization state across the illuminated field on the mask.  The method of claim 13, Wherein the polarization state of the output of the illumination system is optimized such that the absolute value P _LIN of the difference in polarization linearity between each two field points of the field plane in which the mask is disposed does not exceed 10%.  A projection exposure system for exposing a substrate disposed in an area of an image plane of a projection objective lens having at least one image of a pattern of a mask disposed in an area of an object plane of a projection objective lens, wherein the projection exposure system comprises: An illumination system for illuminating a pattern that emits illumination light; A projection objective lens for producing an image of a pattern of an area of an image plane using output light emission oriented in the substrate and having an output polarization state; At least one polarization manipulation device for variably adjusting the output polarization state; At least one polarization measuring device for measuring the output polarization state; A control device for controlling at least one polarization manipulation device as a function of a signal measured from said polarization measurement device, The polarization measuring device is designed to make at least one of position-decomposition and angle-decomposition measurements of the polarization state in the region of the image plane of the projection objective lens, or position-decomposition of the polarization state in the region of pupil plane of the projection objective lens. A projection exposure system characterized in that it is designed to measure. The method of claim 15, A control loop is provided to control the output polarization state in real time, the control loop comprising at least one polarization measuring device; A control unit connected to the polarization measuring device; And at least one polarization manipulation device coupled to the control unit. delete delete delete delete 17. The method according to claim 15 or 16, And at least one polarization manipulation device is arranged in the field plane of the projection exposure system or in the periphery of the field plane. 17. The method according to claim 15 or 16, And at least one polarization manipulation device is arranged in the pupil plane of the projection exposure system or in the periphery of the exposure system. 17. The method according to claim 15 or 16, At least one of the illumination system and the projection objective has at least one optical element that causes disturbances in the polarization distribution on the cross section of the beam, the polarization manipulation device being configured as a compensator for at least partial compensation for disturbances. Projection exposure system. 17. The method according to claim 15 or 16, The at least one polarization manipulation device is characterized in that one or more polarization elements can be inserted into or optionally removed from the illumination beam path or image beam path. 17. The method according to claim 15 or 16, The at least one projection manipulation device is in the form of an exchange device associated with at least two polarizing elements having different effect functions, said exchange device being an exchange device for exchanging polarizing elements having different functions. Projection exposure system. 17. The method according to claim 15 or 16, And at least one polarization manipulation device is in the form of a device for stepwise or continuously changing the effect function of the adjustable polarizing element disposed in the beam path of the projection illumination system. The method of claim 26, The adjustable polarizing element comprises an associated retardation device having at least one retardation element comprised of a stress-birefringent material having an associated actuator that variably adjusts a predetermined stress state in accordance with a predetermined position distribution. Projection exposure system characterized by having. 28. The method of claim 27, The delay device can be adjusted in a variable manner such that the position-resolved change in the effect function of the polarizing element 150 can be made in accordance with a change in the position distribution of the delay effect on the cross section of the delay device. Projection exposure system. 17. The method according to claim 15 or 16, The at least one polarization manipulation device includes at least one retardation device that is movably mounted. 17. The method according to claim 15 or 16, The at least one polarization manipulation device includes at least one retardation device rotatably mounted. 17. The method according to claim 15 or 16, The at least one polarization manipulation device includes at least one polarization element that is at least dispersed or inclined transverse to the optical axis. 17. The method according to claim 15 or 16, The at least one polarization manipulation device comprises a polarizing element comprising a substrate to which at least one isotropic or anisotropic coating is applied comprising a birefringent material. 33. The method of claim 32, And the polarizing element has an associated device for mechanically modifying the polarizing element comprising the coating. The method of claim 33, wherein Wherein the coating comprises a shape birefringent multi-layer system having a plurality of individual layers, wherein at least two or all of the individual layers have a small optical layer thickness compared to the operating wavelength of the illumination light emission. 17. The method according to claim 15 or 16, The at least one polarization manipulation device includes at least one diffractive polarization element having at least one birefringent sub-wavelength structure for generating structure-induced birefringence. 36. The method of claim 35, The at least one polarization manipulation device has at least one polarization element and the various regions with different sub-wavelength structures are arranged alongside each other for the generation of the position-change effect function for the polarization element. Projection exposure system. 17. The method according to claim 15 or 16, The at least one polarization manipulation device has at least one first delay device having a first delay effect and includes at least one delay group having at least one second delay device different from the first delay effect. Projection exposure system. 39. The method of claim 37, At least one retardation device of said retardation group has the same retardation effect on the useful overall cross section. 39. The method of claim 37, At least one retardation device of said retardation group comprises a plurality of individual retardation elements distributed over a cross section of said retardation device and arranged in a raster arrangement to satisfy a surface area. 40. The method of claim 39, Wherein said retardation element of the raster arrangement is different in relation to at least one of the orientation of the crystallographic axis and the absolute value of retardation effect (λ / x). 40. The method of claim 39, The delay group includes, in order, a first delay device having a λ / 4 delay effect, a second delay device having a λ / 2 delay effect, and a third delay device having a λ / 4 delay effect. Projection exposure system. 17. The method according to claim 15 or 16, The at least one polarization manipulation device comprises at least one retardation element, wherein different individual retardation elements with different retardation effects (λ / x) are arranged alongside each other.

Images